


Solving for 'X'

by whelvenwings



Category: Supernatural
Genre: Alternate Universe - High School, Fluff, M/M, Tutor Castiel
Language: English
Status: Completed
Published: 2016-09-21
Updated: 2016-09-21
Packaged: 2018-08-16 11:03:30
Rating: General Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 4,160
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/8099920
Author URL: https://archiveofourown.org/users/whelvenwings/pseuds/whelvenwings
Summary: Castiel is the best in his class at algebra, whereas Dean is more of the opinion that algebra classes are Hell on Earth. When Cas offers to help Dean, he's initially reluctant - but his grades won't rise, so eventually, he has to turn to his least-favourite person in the school for help. But it might not prove as insufferable as he'd first thought...





	

**Author's Note:**

> This fic was written to celebrate my birthday! I hope you're all having an awesome day!! :)

Castiel was the best in the class at algebra, and everyone knew it.

There were people who were close, sure, but Dean definitely wasn’t one of those. Chewing on the end of his pencil, he watched as Cas - wearing a neat blazer, and wearing it well - scribbled letters and numbers on the whiteboard, while Ms Mosely looked on approvingly.

“Then you can multiply by 3,” Cas said, “to solve 'x'. It’s twenty one.”

“Excellent work, Mr Novak,” said Ms Mosely. “You’ve come on leaps and bounds this semester. Please return to your seat.”

Dean rolled his eyes. And Cas saw it, too, as he resumed his seat - the one right in front of Dean’s. It was obvious from the way that Cas’ lips turned down, and his cheeks flushed. Even the tips of his ears went a little pink; Dean had the perfect view of them, from right behind him.

He willed himself not to feel bad. Castiel’s ego had to be sky-high, seeing as he was ruling the school as far as grades went. He could probably use being taken down a peg or two.

Even still, it stuck in Dean’s mind all the way through the lesson, even when Ms Mosely set them some algebra problems to do individually and Dean could see Castiel’s pencil flying across the page, solving the equations in record time, while Dean himself scratched aimlessly at his notebook - stuck on the first one. When the bell was about to ring, he leaned forward and flicked Cas on the back, hard.

“What’s the answer to number one?” he whispered, under the cover of Ms Mosely reaching down into her desk and clattering open her drawer. Castiel only looked at Dean for a very, very long moment - and let his gaze linger in a way that made Dean very, very aware of the fray in the shoulder of his leather jacket, and the cheapness of his t-shirt, and the fact that he hadn’t had time to style his hair right that morning.

“What?” Dean demanded. Castiel said nothing at all - and then, very pointedly, he rolled his eyes at Dean, and turned away.

Dean fumed until the bell rang five minutes later, and then stormed out of the class.

*

It didn’t help that Castiel was - damn him, Dean thought - _cute_ , though the word didn’t seem to entirely sum up the way that his blue eyes could catch Dean’s from across a room full of people... or the way that his profile, or his lean physique, or his thoughtful, serious expressions, could take Dean’s breath away. It really didn’t _help._

It wasn’t as though Dean were going to do anything _about_ the fact that he thought Castiel was the most attractive person he’d ever seen, though. There would be no point. Sure, Cas was cute, but his personality was… decidedly less cute. In fact, it was downright unpleasant. He was so unpleasant that Dean couldn’t help thinking about _how_ unpleasant he was, all the time. On Wednesdays, it was particularly bad; Wednesdays was when they had algebra together, which was Castiel’s time to shine - shine like the goddamn algebraic star of Bethlehem, leading all his lowly peasant peers towards the light.

“This is for you,” said a voice, startling Dean out of his thoughts; he slammed his locker door closed to find, on the other side of it, looking particularly good - particularly _grumpy,_ Dean corrected himself - Castiel Novak.

He thrust a book in Dean’s face. Dean grimaced, just to make sure Cas was aware of how little Dean wanted to be a part of this conversation - and then he grabbed the book, roughly.

 _Solving for ‘x’: A Guide to Basic Algebra,_ said the front cover. Dean read it, his cheeks reddening.

“What is this?” he demanded. “Is this a joke?”

“What - no,” Castiel said, looking genuinely taken aback. “Why would I…”

“I know I’m not as great at math as you are, Good Will Hunting, but I don’t need you making fun,” Dean said, shoving the book back against Cas’ chest. “Pick on someone _else_ who isn’t as good as you, OK? You’ve got the whole damn class.”

Castiel’s frown of confusion turned to a scowl.

“I was just trying to help,” he said. “You didn’t get any of the answers right in the most recent test -”

“Oh,” Dean said, his blush worsening. “Oh, you’re paying attention to when I fail, now. Of course you are.”

“You pay attention to when I succeed, apparently,” Cas said acidly, and Dean snorted.

“Oh, like anyone could miss it?” He put his hands up to his chest, like a puppy. “‘Please, Ms Mosely, pick me, Ms Mosely, I know the answer, Ms Mosely…’”

Castiel used the book in his hands to whack Dean hard on the arm.

“Shut _up_ ,” he said, glaring at Dean. “I only wanted to help. I didn’t realise you were going to be such an _ass_ about it.”

Turning on his heel, he stalked away. Dean watched him go, caught between anger and slight guilt, just like he usually was after any kind of interaction with Castiel.

 _Whatever,_ he thought. _He’s got it all wrong anyway. It’s not like I need his help in math._

*

Dean needed help in math.

“You need to apply yourself, Mr Winchester,” Mr Mosely said reprovingly, dropping his latest homework back onto his desk. Dean pulled it towards him, seeing only big red crosses.

He swallowed hard, and tried to forget that he really _had_ applied himself to this homework. He’d thought that he’d got at least half of them right, and it had taken him over two hours. In front of him, he could see that Castiel was sitting very still, with a paper that read ‘Well done, Castiel’ upright in his hands.

“Yeah, okay, I get it,” Dean hissed, as the rest of the class murmured to each other while the homeworks were returned. “You got full marks. Put it away, Novak, no one cares.”

Castiel turned around, looking incensed. Dean quailed a little inside, but made certain not to show it, lifting his chin and narrowing his eyes.

“You need help with math,” Castiel said. “That’s not my fault.”

“So what if I do?” Dean said angrily, trying to keep his voice down.

“You should have accepted my offer, before.”

Dean struggled with himself.

“So what if I should’ve?” he said. Cas narrowed his eyes.

“You want the book?” he asked suspiciously. Dean sighed. He couldn’t believe he was having to do this - having to ask Castiel Novak for any kind of help. The guy was insufferable. But Dean was failing, hard, so he’d take the stupid book.

“Yeah,” he said. Sullenly.

Was he imagining the way that Cas’ mouth turned up, just a little? He definitely wasn’t imagining the way the idea of that made his heartbeat quicken. Dean scowled. Now was _not_ the time to be remembering how cute Cas was.

“Fine. I’ll be at the library after school. Pick it up from me then.” Cas quickly turned back to face the front as Ms Mosely started to speak, beginning the lesson in earnest. As usual, within thirty seconds, he had his hand in the air, ready to impart some of his mighty knowledge. Cas couldn’t see Dean rolling his eyes from his seat, so Dean made sure to kick his chair every time Ms Mosely called on him throughout the class.

It was just a kind of payback, Dean figured. Life had blessed Cas with a head for mathematics; he could deal with a little bit of teasing for it.

*

The library was almost deserted after class hours were over; Dean found this out when he went to get the book from Castiel, since he had never set foot in the school library at all up until that point. The place smelled like paper and dust, and was full of people who stared at him as though he were a coffee stain on the carpet.

He strode through the shelves, trying to seem confident, until he found the table where Castiel was sitting - rocking backwards on his chair, nose buried in a book. Dean smirked, and stepped more quietly; when he was right behind Castiel, he hooked his foot around one of the chair’s legs and jerked. The chair swung backwards; Castiel flung his arms out with a yelp, reaching for the desk in front of him to steady himself, and missing it - he tipped back too far, and the only thing that stopped Cas from falling hard to the ground was Dean, standing right behind him, catching him easily and pushing the chair back onto four legs.

Cas swung around, and glared at him.

“What?” Dean said, innocently, stepping out from behind Cas and leaning in a half-sit against his desk. He adopted a mock-concerned tone. “If you will lean back on your chair like that, Cas, accidents will happen.”

“Only if someone like _you_ happens to walk in,” Cas said, his tone more grumbling than actually angry. Dean smirked.

“I’m flattered,” he said, and winked.

Cas’ cheeks flushed, and he reached across his desk, swept up a book, and shoved it at Dean.

“Take it,” he said. “Go.”

Dean took the book - with considerably better grace than last time, too - and opened it up. Inside, he could see nothing but endless equations, letters and numbers crawling over each other, mixing and twisting and waiting to confuse him.

“Well?” Castiel said, a little impatiently. “Is there something wrong with it?”

Dean snorted.

“It’s in a foreign language, that’s what’s wrong with it,” he said. Castiel frowned, reaching for it.

“But it should be in English…”

“No, I mean -” Dean laughed, then, for real, while Cas looked at him blankly. _Cute,_ a voice in Dean’s head whispered. He told it sternly to shut up. “I mean the algebra, man. It might as well be hieroglyphs, I look at it and I got squat.”

Cas stared at him for a long, long moment.

“Well,” he said, “you haven’t opened it at the first page, to start with.”

Dean flipped to page one.

“Two ‘x’ plus three equals seventeen,” he read out. “Solve for ‘x’.”

Cas looked at Dean expectantly; Dean raised his eyebrows, and shrugged.

“Uh… three?” he said, like he couldn’t care less, and Cas sighed.

“Whatever you do to one side of the equation, you must do to the other,” he said. “So…”

“So…” Dean said, feeling stupid. _Both sides?_ The equation had sides? “So if I take one out to dinner, I gotta give the other one at least a look-in for brunch?”

Cas gave him an exasperated look.

“You don’t even _try,_ ” he said. Dean shrugged, irritated.

“What’s the point? I’m not going to get it anyway.”

Castiel put down his own book, at that, and looked at him - really _looked_ at him, frankly and honestly, without any of his usual narrow-eyed suspicion. Dean shifted under his gaze, but didn’t look away; if he told the truth, there was something actually quite - quite attractive, about being stared at like this, by Castiel -

“Sit down,” Cas said, and pointed to the chair next to his, tucked in under his desk.

“What -”

“Sit down.”

“But - come on, man, it’s after school -”

“Do you want to get better at algebra?”

“No,” Dean said truculently.

Cas only raised an eyebrow.

“Fine. _Yes._ But not like this, not with extra studying…”

“Oh,” Cas said. “You should have just said so before. I would have given you this magical math-skill potion I have in my pocket.”

Dean eyed him, and after a moment, Cas offered him a dry smile.

“You’re an ass,” Dean said, and sat down, and the smile widened.

“We’ll start at the beginning,” Cas said, taking the book out of Dean’s hands and opening it to the first page. “Now, equations are divided into two halves, separated by an equals sign. Like this.” He pointed to the example on the page that Dean had read out. He was sitting close, Dean couldn’t help noticing, as he nodded. Dean could smell the scent of mint, and laundry powder, and something else - a person smell. Cas’ smell, Dean thought, finding himself committing it to memory by taking a deeper breath in. He scowled at himself. _Stop acting like a creep._

“See,” Cas said, pulling a blank piece of paper towards him and starting to scribble, continuing to explain. Dean tried to tune back into what he was saying, though his attention almost immediately wandered to Cas’ jawline, and his blue eyes, and the hair that curled at the back of his neck - he always liked watching it in class, for some reason, but up close it was even more tempting to touch -

“Now you try,” Cas said. Dean cleared his throat, a flush on his cheeks.

“Uh,” he said. “Sorry. Can you go through it one more time?”

*

Having Castiel as a tutor for math was both better and worse than Dean could ever have expected.

It was better, because Dean got to see Cas almost every day, now - something that he thought he would have minded, but somehow simply _didn’t._ It was so much easier than he ever could have predicted, just making conversation with Cas as they worked together - Dean caught himself laughing at Cas’ sarcasm, and his cluelessness, and couldn’t bring himself to stop it; not even to preserve the carefully-built wall of dislike that he’d been cementing in place for quite some time. The wall was starting to feel less and less sturdy the longer they spent together.

Which left Dean with a problem - a problem that made Cas being his math tutor _so_ much worse than Dean could have foreseen. Because before, Dean had thought Cas was cute, but with a horrible personality. And now, Dean was finding out that Cas was cute, and actually had a personality to match; sure, he was prickly and weird to start with, but once you got to know him, Cas was kind and funny and deep, and all-around pretty much everything that Dean would love to see sitting opposite him at Ellen’s Diner, sharing a milkshake, on a date.

But it was impossible to find a way to _tell_ Cas that. Dean knew that Cas was attracted to boys - finding that out had been like putting his heart in a bouncy house, he still remembered their conversation - but he had no idea whether Cas was attracted to _him,_ specifically, in a dating kind of way. And if he wasn’t, and Dean came onto him, then Dean would lose - well, there wasn’t a lot of past behind them, only a few weeks’ of tutoring and several years of mutual dislike, but Dean couldn’t help feeling the weight of their possibility. The future looked brighter with Castiel in Dean’s life, and Dean felt ill every time he considered the risks of confessing his growing feelings. To go back to how they’d been - sniping at each other, fighting all the time - would be bad enough, but Dean thought that after he’d told Cas how he felt and been rejected, it’d be worse than that. There’d be no sniping, just awkward silence. No fighting, only avoiding each other wherever they could and being polite when they accidentally met each other’s eyes. _God._ Dean shivered.

“Are you cold?” Cas said, reaching instinctively for the blazer that he’d laid over the back of his chair. Dean eyed it. _No. Don’t. Don’t -_

“Yeah,” said Dean’s treacherous mouth. “A bit. Do you mind?”

“Not at all,” Cas said, handing Dean the blazer - for a moment, Dean thought Cas was going to reach over and put it round Dean’s shoulders himself, but at the last moment, he seemed to change his mind and simply dropped it in Dean’s lap.

Dean spent the rest of their session draped in Cas’ coat, the one that he’d always hated before. It was soft on the inside, and smelled of Cas.

By the end of the session, Dean didn’t hate it anymore.

*

Today. Today was the day.

Dean took his seat beside Castiel as usual, pasting on a confident smirk.

“Hello, Dean.”

“Hey, Cas,” Dean said easily. In his mind, he kept compulsively going over the plan, round and round and round again. When should he do it? At the beginning of the session, or the end?

The right moment would present itself, Dean was sure. For now, he only opened up his algebra book, and dived into problem-solving. Occasionally, he asked Cas for help; mostly, he worked in silence. He’d got a lot better, recently, despite the fact that his concentration on Cas’ algebra teaching was never incredibly good.

“So… you like milkshakes?” Dean said, after they’d been working for about half an hour. Cas glanced over at him - Dean’s breath caught, though he would have sworn it didn’t - and narrowed his eyes.

“Are you stuck?”

“No,” Dean said, defensively. “I’m not always stuck every time I bring up a random topic, you know. I was just _wondering._ ”

Cas rolled his eyes.

“Well, fine. I like milkshakes, yes.”

“And burgers?”

Cas’ frown deepened.

“Dean, what are you getting at?”

“What, can’t a guy ask his friend if he likes burgers, now?”

Cas sighed.

“I like burgers, yes.”

“OK. Good.” Dean ticked a couple of boxes in his head. So, the date at Ellen’s Diner would work, then. Now, Dean just had to actually _ask._

His heart rate started to rise. Maybe it would be better to just leave it, for today? He’d figured out that Cas liked burgers and milkshakes; that was definitely a step forward. And he could take the next step forward tomorrow, by finding out if Cas liked… going out to eat. And the next day, he could ask whether Cas liked going out to eat with _friends._ And the next…

Dean cut himself off. If he didn’t ask today, he didn’t think he’d ever be able to work up the courage. He swallowed hard, and looked over at Cas, who was scribbling something on a piece of rough paper - something that looked complicated, and algebraic.

He was beautiful, Dean thought. Really, he was. Dean wasn’t sure how he’d missed exactly how amazing Castiel was, for all of these years.

Dean took a deep breath, and released it. He had to try. He couldn’t go on with their friendship with this big question mark hanging in his head all the time. He had to at least _try._

He reached over, and gently tugged at the piece of paper that Cas was writing on. Cas looked up at him in surprise, but allowed Dean to pull it away to his side of the desk, and uncap his pen.

“Dean, what are you doing?” Cas said.

“I’m just writing something,” Dean said, running over the numbers in his mind one last time before beginning to write them down - being careful over each stroke of his pen over the paper. He couldn’t mess this up, or the whole thing wouldn’t work.

“Dean,” Cas said, dryly, “you’ve been getting a lot better, but I don’t think you’re going to be able to -”

“I’m not trying to solve _your_ equations,” Dean said, shoving the paper back over to Cas roughly, trying to disguise the way his hands were shaking just a little bit with the nerves. “I’m giving you a different one to do.”

“An equation… set by you?” Cas said doubtfully, picking up the paper. “Where did you find it?”

“I made it up,” Dean said, and Cas looked even more sceptical. “Come on, just give it a go.”

Cas’ eyes were full of misgivings, but nevertheless he raised the paper up to look at it.

 _4(2u + m x e) = (8 ÷ 2) x (d⁶ x d² + u),_ he read, his mouth moving along with the words, Dean following along - each number and letter branded into his memory. He looked over at Dean.

“You want me to solve this? Were you stuck on it at home?”

“Not exactly,” Dean said. “It’s - it’s not the homework I’m stuck on.”

Cas only stared at him, confused. Dean waved his hand.

“Go on,” he said. “Do that thing you do.”

Cas, still flicking glances of suspicion towards Dean, set the paper down on the table and picked up his mechanical pencil. After a moment’s thought, he began to talk, scribbling on the paper as he did so.

“It’s not a particularly difficult equation to simplify,” he said. “Eight divided by two is four, and I’m supposed to multiply what’s in _these_ brackets here by four, but since there’s a multiplication by four on the other side, too, I can cancel those out.”

Dean watched him write,

_2u + m x e = d⁶ x d² + u_

“Now, I take away the ‘u’ on this side,” Cas said, speaking absently; he’d become so used to explaining his method to Dean over the past few weeks that Dean wondered if he was even aware he was still doing it. “So I must also do it on this side. Following the order of operations, ‘m’ multiplies with ‘e’ before being added to ‘u’, so we can shorten that to ‘me’. And put it at the beginning, so. And on the other side, ‘d’ to the power of six multiplied by ‘d’ to the power of two becomes ‘d’ to the power of eight.”

He wrote it out, while Dean held his breath.

_me + u = d⁸_

“There,” Cas said. “It can’t be solved more than that.”

Dean could feel his heart pounding, waiting for the penny to drop.

“Uh, well,” he said. “Actually, you could, um, tell me the answer.” He leaned over, and scrawled a question mark after the equation that Cas had written.

_me + u = d⁸ ?_

“Me plus you equals ‘d’ to the power of…” Cas began, confused, and then - suddenly - his eyes went wide. “Date?” He turned to look at Dean, looking stunned, a slight pink tinge appearing on his cheeks.

Dean lifted one shoulder.

“Well,” he said. “You know… you like burgers, and milkshakes, and so do I, so… it’d just be weird at this point if we didn’t go get them together, right?” He tried a winning smile, but his nerves made it come out a little wrong. Cas was giving him no clue as to whether he stood any chance at all.

“You really want to go on a date… with me?”

“Well - yeah, Cas,” Dean said.

“But you - we - I mean…” Cas said, tongue-tied and ineloquent for maybe the first time since Dean had known him. Dean managed to huff a little laugh.

“Yeah,” he said. “You’re right. It’s dumb. We don’t get along, and -”

“Well, but -”

“You know, if you don’t see me that way, then I guess it’s just -”

“Dean -”

“I mean, it’s fine, is what I’m trying to say, and I hope this doesn’t make it awkward between us, and -”

“Dean, would you stop trying to feel let down when I’m trying to tell you _yes_?”

Dean froze.

“You - you - what?” he said, weakly. Cas was watching him, his gaze profound and intense, a tiny, tiny smile hidden at the corner of his mouth.

“I said, yes,” he repeated. “I want to go on a date with you.”

Dean could only stare at him, speechless. Never, not in a single one of his imaginings, had he pictured Castiel saying _yes._

Cas picked up the piece of paper, and looked down again at the equation that he’d written. Next to Dean’s question mark, he put a single check mark. _Correct._

Dean received many, many more check marks in algebra over the years to come - but not one of them, not a single one, meant as much to him as that one, pencilled in by Castiel Novak.

“Just one thing,” Cas said, as Dean reached over for the page, wanting to hold it in his hands, check that it was real. “If we start this…”

Dean went still, catching Cas’ serious tone.

“You’d better not solve for ex,” Cas said. “Because you’ll be stuck with me for a while.”

Dean laughed, and rolled his eyes.

“I’ve been stuck on you since forever already,” he said. “I think being stuck _with_ you would suit me just fine.”

He’d held back for so long, and now Cas was blushing down at his books, smiling in the way that made Dean’s heart skip a beat. He leaned over, and kissed Cas’ cheek - a quick, nervous kiss, his cheeks furiously red with the shock of his own daring. Cas clapped his fingertips to the place where Dean’s lips had landed, his own mouth forming a perfect ‘o’ of surprise, before breaking into a smile.

“Tonight, then?” he said, and Dean - barely able to keep himself from bursting with happiness - nodded his head.

“Tonight,” he said.

Turned out, Cas being the best in the class at algebra was actually pretty useful, after all.


End file.
